Avian flu, euthanasia claim 80 tigers at Thai zoo

Oct 22, 2004 (CIDRAP News) – About 80 tigers have died or been euthanized at a Thai zoo in the wake of an apparent avian influenza outbreak that may have been caused by consumption of infected chicken carcasses, news agencies are reporting.

Thirty-two tigers have died of H5N1 avian flu at the Sri Racha Tiger Zoo, about 50 miles from Bangkok, and 51 more were euthanized, according to a Reuters report today.

Tests on more than 20 tigers showed they were infected with the H5N1 virus, Thai officials said this week. None of the 57 zookeepers has gotten sick from caring for ailing tigers at the zoo, one official told Reuters.

The zoo had 400 endangered tigers before the outbreak began. Reports differ as to when the tigers started dying, but the Associated Press said the zoo has been closed to the public since Oct 19. Many of the tigers were euthanized late this week, news agencies reported.

“We had to perform mercy killings on those tigers because they were in critical conditions,” Preecha Ratanaporn, with the Ministry of Natural Resources and the Environment, told Reuters. “We are monitoring four or five more of these tigers. If they show no symptoms in a week, we can declare the zoo free of bird flu.”

The tigers were fed raw chicken carcasses, which officials said were believed to be infected with H5N1 avian flu. That strain has killed 31 people in Southeast Asia since late January, led to the culling of millions of poultry, and claimed a few victims among large cats such as leopards and tigers.

Health experts worry that avian flu could mutate in a mammal host by combining with a human flu virus. Such a shift in the virus could create a strain that would spread easily from person to person and to which people have no immunity. Those circumstances in the past have led to global flu pandemics.

The World Health Organization has said tigers are not known to harbor human flu viruses, so they aren’t likely to provide an opportunity for the avian strain to combine with human strains, Reuters reported.